TF SavedModel: Split off a reader from the loader module

PiperOrigin-RevId: 204468340

5 files changed, 271 insertions, 64 deletions

diff --git a/tensorflow/cc/saved_model/BUILD b/tensorflow/cc/saved_model/BUILD
index 06a3be18e0..730b1b669b 100644
--- a/tensorflow/cc/saved_model/BUILD
+++ b/tensorflow/cc/saved_model/BUILD
@@ -34,6 +34,35 @@ cc_library(
 )
 
 cc_library(
+    name = "reader",
+    srcs = ["reader.cc"],
+    hdrs = ["reader.h"],
+    deps = [
+        ":constants",
+        "//tensorflow/core:lib",
+        "//tensorflow/core:protos_all_cc",
+    ],
+)
+
+tf_cc_test(
+    name = "reader_test",
+    srcs = ["reader_test.cc"],
+    data = [
+        ":saved_model_half_plus_two",
+    ],
+    linkstatic = 1,
+    deps = [
+        ":constants",
+        ":reader",
+        ":tag_constants",
+        "//tensorflow/core:lib",
+        "//tensorflow/core:test",
+        "//tensorflow/core:test_main",
+        "//tensorflow/core:testlib",
+    ],
+)
+
+cc_library(
     name = "loader",
     hdrs = ["loader.h"],
     deps = [
@@ -54,6 +83,7 @@ cc_library(
     hdrs = ["loader.h"],
     deps = [
         ":constants",
+        ":reader",
     ] + if_not_mobile([
         "//tensorflow/core:core_cpu",
         "//tensorflow/core:framework",
diff --git a/tensorflow/cc/saved_model/loader.cc b/tensorflow/cc/saved_model/loader.cc
index faa1e378d0..07807ed2f3 100644
--- a/tensorflow/cc/saved_model/loader.cc
+++ b/tensorflow/cc/saved_model/loader.cc
@@ -18,8 +18,10 @@ limitations under the License.
 #include <unordered_set>
 
 #include "tensorflow/cc/saved_model/constants.h"
+#include "tensorflow/cc/saved_model/reader.h"
 #include "tensorflow/core/lib/io/path.h"
 #include "tensorflow/core/lib/monitoring/counter.h"
+#include "tensorflow/core/lib/strings/str_util.h"
 #include "tensorflow/core/lib/strings/strcat.h"
 #include "tensorflow/core/platform/env.h"
 #include "tensorflow/core/platform/protobuf_internal.h"
@@ -43,56 +45,6 @@ auto* load_latency = monitoring::Counter<1>::New(
 constexpr char kLoadAttemptFail[] = "fail";
 constexpr char kLoadAttemptSuccess[] = "success";
 
-Status ReadSavedModel(const string& export_dir, SavedModel* saved_model_proto) {
-  const string saved_model_pb_path =
-      io::JoinPath(export_dir, kSavedModelFilenamePb);
-  if (Env::Default()->FileExists(saved_model_pb_path).ok()) {
-    return ReadBinaryProto(Env::Default(), saved_model_pb_path,
-                           saved_model_proto);
-  }
-  const string saved_model_pbtxt_path =
-      io::JoinPath(export_dir, kSavedModelFilenamePbTxt);
-  if (Env::Default()->FileExists(saved_model_pbtxt_path).ok()) {
-    return ReadTextProto(Env::Default(), saved_model_pbtxt_path,
-                         saved_model_proto);
-  }
-  return Status(error::Code::NOT_FOUND,
-                "Could not find SavedModel .pb or .pbtxt at supplied export "
-                "directory path: " +
-                    export_dir);
-}
-
-string GetTagsAsString(const std::unordered_set<string>& tags) {
-  string tags_as_string = "{ ";
-  for (const string& tag : tags) {
-    tags_as_string = strings::StrCat(tags_as_string, tag, " ");
-  }
-  tags_as_string = strings::StrCat(tags_as_string, "}");
-  return tags_as_string;
-}
-
-Status FindMetaGraphDefToLoad(const SavedModel& saved_model_proto,
-                              const std::unordered_set<string>& tags,
-                              MetaGraphDef* meta_graph_def_to_load) {
-  for (const MetaGraphDef& meta_graph_def : saved_model_proto.meta_graphs()) {
-    // Get tags from the meta_graph_def.
-    std::unordered_set<string> graph_tags;
-    for (const string& tag : meta_graph_def.meta_info_def().tags()) {
-      graph_tags.insert(tag);
-    }
-    // Match with the set of tags provided.
-    if (graph_tags == tags) {
-      *meta_graph_def_to_load = meta_graph_def;
-      return Status::OK();
-    }
-  }
-  return Status(error::Code::NOT_FOUND,
-                "Could not find meta graph def matching supplied tags: " +
-                    GetTagsAsString(tags) +
-                    ". To inspect available tag-sets in the SavedModel, please "
-                    "use the SavedModel CLI: `saved_model_cli`");
-}
-
 Status LoadMetaGraphIntoSession(const MetaGraphDef& meta_graph_def,
                                 const SessionOptions& session_options,
                                 std::unique_ptr<Session>* session) {
@@ -235,18 +187,8 @@ Status LoadSavedModelInternal(const SessionOptions& session_options,
                               const string& export_dir,
                               const std::unordered_set<string>& tags,
                               SavedModelBundle* const bundle) {
-  if (!MaybeSavedModelDirectory(export_dir)) {
-    return Status(error::Code::NOT_FOUND,
-                  "SavedModel not found in export directory: " + export_dir);
-  }
-  LOG(INFO) << "Loading SavedModel with tags: " << GetTagsAsString(tags)
-            << "; from: " << export_dir;
-
-  SavedModel saved_model_proto;
-  TF_RETURN_IF_ERROR(ReadSavedModel(export_dir, &saved_model_proto));
-
-  TF_RETURN_IF_ERROR(
-      FindMetaGraphDefToLoad(saved_model_proto, tags, &bundle->meta_graph_def));
+  TF_RETURN_IF_ERROR(ReadMetaGraphDefFromSavedModel(export_dir, tags,
+                                                    &bundle->meta_graph_def));
 
   TF_RETURN_IF_ERROR(LoadMetaGraphIntoSession(
       bundle->meta_graph_def, session_options, &bundle->session));
@@ -288,8 +230,8 @@ Status LoadSavedModel(const SessionOptions& session_options,
     return end_microseconds - start_microseconds;
   }();
   auto log_and_count = [&](const string& status_str) {
-    LOG(INFO) << "SavedModel load for tags " << GetTagsAsString(tags)
-              << "; Status: " << status_str << ". Took "
+    LOG(INFO) << "SavedModel load for tags { " << str_util::Join(tags, " ")
+              << " }; Status: " << status_str << ". Took "
               << load_latency_microsecs << " microseconds.";
     load_attempt_count->GetCell(export_dir, status_str)->IncrementBy(1);
   };
diff --git a/tensorflow/cc/saved_model/reader.cc b/tensorflow/cc/saved_model/reader.cc
new file mode 100644
index 0000000000..2146c8a197
--- /dev/null
+++ b/tensorflow/cc/saved_model/reader.cc
@@ -0,0 +1,88 @@
+/* Copyright 2018 The TensorFlow Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+==============================================================================*/
+
+#include "tensorflow/cc/saved_model/reader.h"
+
+#include <unordered_set>
+
+#include "tensorflow/cc/saved_model/constants.h"
+#include "tensorflow/core/lib/io/path.h"
+#include "tensorflow/core/lib/strings/str_util.h"
+#include "tensorflow/core/lib/strings/strcat.h"
+#include "tensorflow/core/platform/env.h"
+#include "tensorflow/core/protobuf/saved_model.pb.h"
+
+namespace tensorflow {
+namespace {
+
+Status ReadSavedModel(const string& export_dir, SavedModel* saved_model_proto) {
+  LOG(INFO) << "Reading SavedModel from: " << export_dir;
+
+  const string saved_model_pb_path =
+      io::JoinPath(export_dir, kSavedModelFilenamePb);
+  if (Env::Default()->FileExists(saved_model_pb_path).ok()) {
+    return ReadBinaryProto(Env::Default(), saved_model_pb_path,
+                           saved_model_proto);
+  }
+  const string saved_model_pbtxt_path =
+      io::JoinPath(export_dir, kSavedModelFilenamePbTxt);
+  if (Env::Default()->FileExists(saved_model_pbtxt_path).ok()) {
+    return ReadTextProto(Env::Default(), saved_model_pbtxt_path,
+                         saved_model_proto);
+  }
+  return Status(error::Code::NOT_FOUND,
+                "Could not find SavedModel .pb or .pbtxt at supplied export "
+                "directory path: " +
+                    export_dir);
+}
+
+Status FindMetaGraphDef(const SavedModel& saved_model_proto,
+                        const std::unordered_set<string>& tags,
+                        MetaGraphDef* meta_graph_def) {
+  LOG(INFO) << "Reading meta graph with tags { " << str_util::Join(tags, " ")
+            << " }";
+  for (const MetaGraphDef& graph_def : saved_model_proto.meta_graphs()) {
+    // Get tags from the graph_def.
+    std::unordered_set<string> graph_tags;
+    for (const string& tag : graph_def.meta_info_def().tags()) {
+      graph_tags.insert(tag);
+    }
+    // Match with the set of tags provided.
+    if (graph_tags == tags) {
+      *meta_graph_def = graph_def;
+      return Status::OK();
+    }
+  }
+  return Status(
+      error::Code::NOT_FOUND,
+      strings::StrCat(
+          "Could not find meta graph def matching supplied tags: { ",
+          str_util::Join(tags, " "),
+          " }. To inspect available tag-sets in the SavedModel, please "
+          "use the SavedModel CLI: `saved_model_cli`"));
+}
+
+}  // namespace
+
+Status ReadMetaGraphDefFromSavedModel(const string& export_dir,
+                                      const std::unordered_set<string>& tags,
+                                      MetaGraphDef* const meta_graph_def) {
+  SavedModel saved_model_proto;
+  TF_RETURN_IF_ERROR(ReadSavedModel(export_dir, &saved_model_proto));
+  TF_RETURN_IF_ERROR(FindMetaGraphDef(saved_model_proto, tags, meta_graph_def));
+  return Status::OK();
+}
+
+}  // namespace tensorflow
diff --git a/tensorflow/cc/saved_model/reader.h b/tensorflow/cc/saved_model/reader.h
new file mode 100644
index 0000000000..5815108df2
--- /dev/null
+++ b/tensorflow/cc/saved_model/reader.h
@@ -0,0 +1,39 @@
+/* Copyright 2018 The TensorFlow Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+==============================================================================*/
+
+/// Functions to read the SavedModel proto, or parts of it.
+
+#ifndef TENSORFLOW_CC_SAVED_MODEL_READER_H_
+#define TENSORFLOW_CC_SAVED_MODEL_READER_H_
+
+#include <string>
+#include <unordered_set>
+
+#include "tensorflow/core/lib/core/status.h"
+#include "tensorflow/core/protobuf/meta_graph.pb.h"
+
+namespace tensorflow {
+
+// Reads the SavedModel proto from saved_model.pb(txt) in the given directory,
+// finds the MetaGraphDef that matches the given set of tags and writes it to
+// the `meta_graph_def` parameter. Returns a failure status when the SavedModel
+// file does not exist or no MetaGraphDef matches the tags.
+Status ReadMetaGraphDefFromSavedModel(const string& export_dir,
+                                      const std::unordered_set<string>& tags,
+                                      MetaGraphDef* const meta_graph_def);
+
+}  // namespace tensorflow
+
+#endif  // TENSORFLOW_CC_SAVED_MODEL_READER_H_
diff --git a/tensorflow/cc/saved_model/reader_test.cc b/tensorflow/cc/saved_model/reader_test.cc
new file mode 100644
index 0000000000..620e9c2eec
--- /dev/null
+++ b/tensorflow/cc/saved_model/reader_test.cc
@@ -0,0 +1,108 @@
+/* Copyright 2018 The TensorFlow Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+==============================================================================*/
+
+#include "tensorflow/cc/saved_model/reader.h"
+
+#include "tensorflow/cc/saved_model/constants.h"
+#include "tensorflow/cc/saved_model/tag_constants.h"
+#include "tensorflow/core/lib/core/status.h"
+#include "tensorflow/core/lib/core/status_test_util.h"
+#include "tensorflow/core/lib/io/path.h"
+#include "tensorflow/core/lib/strings/str_util.h"
+#include "tensorflow/core/platform/test.h"
+
+namespace tensorflow {
+namespace {
+
+constexpr char kTestDataPbTxt[] =
+    "cc/saved_model/testdata/half_plus_two_pbtxt/00000123";
+constexpr char kTestDataSharded[] =
+    "cc/saved_model/testdata/half_plus_two/00000123";
+
+class ReaderTest : public ::testing::Test {
+ protected:
+  ReaderTest() {}
+
+  void CheckMetaGraphDef(const MetaGraphDef& meta_graph_def) {
+    const auto& tags = meta_graph_def.meta_info_def().tags();
+    EXPECT_TRUE(std::find(tags.begin(), tags.end(), kSavedModelTagServe) !=
+                tags.end());
+    EXPECT_NE(meta_graph_def.meta_info_def().tensorflow_version(), "");
+    EXPECT_EQ(
+        meta_graph_def.signature_def().at("serving_default").method_name(),
+        "tensorflow/serving/predict");
+  }
+};
+
+TEST_F(ReaderTest, TagMatch) {
+  MetaGraphDef meta_graph_def;
+
+  const string export_dir =
+      io::JoinPath(testing::TensorFlowSrcRoot(), kTestDataSharded);
+  TF_ASSERT_OK(ReadMetaGraphDefFromSavedModel(export_dir, {kSavedModelTagServe},
+                                              &meta_graph_def));
+  CheckMetaGraphDef(meta_graph_def);
+}
+
+TEST_F(ReaderTest, NoTagMatch) {
+  MetaGraphDef meta_graph_def;
+
+  const string export_dir =
+      io::JoinPath(testing::TensorFlowSrcRoot(), kTestDataSharded);
+  Status st = ReadMetaGraphDefFromSavedModel(export_dir, {"missing-tag"},
+                                             &meta_graph_def);
+  EXPECT_FALSE(st.ok());
+  EXPECT_TRUE(str_util::StrContains(
+      st.error_message(),
+      "Could not find meta graph def matching supplied tags: { missing-tag }"))
+      << st.error_message();
+}
+
+TEST_F(ReaderTest, NoTagMatchMultiple) {
+  MetaGraphDef meta_graph_def;
+
+  const string export_dir =
+      io::JoinPath(testing::TensorFlowSrcRoot(), kTestDataSharded);
+  Status st = ReadMetaGraphDefFromSavedModel(
+      export_dir, {kSavedModelTagServe, "missing-tag"}, &meta_graph_def);
+  EXPECT_FALSE(st.ok());
+  EXPECT_TRUE(str_util::StrContains(
+      st.error_message(),
+      "Could not find meta graph def matching supplied tags: "))
+      << st.error_message();
+}
+
+TEST_F(ReaderTest, PbtxtFormat) {
+  MetaGraphDef meta_graph_def;
+
+  const string export_dir =
+      io::JoinPath(testing::TensorFlowSrcRoot(), kTestDataPbTxt);
+  TF_ASSERT_OK(ReadMetaGraphDefFromSavedModel(export_dir, {kSavedModelTagServe},
+                                              &meta_graph_def));
+  CheckMetaGraphDef(meta_graph_def);
+}
+
+TEST_F(ReaderTest, InvalidExportPath) {
+  MetaGraphDef meta_graph_def;
+
+  const string export_dir =
+      io::JoinPath(testing::TensorFlowSrcRoot(), "missing-path");
+  Status st = ReadMetaGraphDefFromSavedModel(export_dir, {kSavedModelTagServe},
+                                             &meta_graph_def);
+  EXPECT_FALSE(st.ok());
+}
+
+}  // namespace
+}  // namespace tensorflow